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27SP4

Twenty-seven-inch direct-view television picture tube with aluminized gray-filter screen, low-voltage electrostatic focusing, magnetic deflection, and an external ion trap. Its anode is rated around 20 kV.

Directly heatedCold cathodeCommon cathodeDissimilarSpecialized

Sections: 1
Base: 12L
Socket code: DUODECAL6
Base pins: 12
Nominal heater: 6.3 V / 600 mA

Description

The 27SP4 is a direct-view television picture tube with an aluminized grey-filter screen, low-voltage electrostatic focusing, magnetic deflection and an external ion trap.

Socket description

Small-shell Duodecal 6-contact CRT base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 12L
Socket code: DUODECAL6
Base pins: 12
Nominal heater voltage: 6.3 V
Nominal heater current: 600 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

12L - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Cathode Ray

X-ray radiationInterelectrode capacitances

Max plate voltage: 20000 V
Max screen voltage: 500 V
Rectifier max heater-cathode voltage: 410 V

Direct-view television CRT; high-voltage electrode rating mapped to MaxPlateVoltage as the section high-voltage limit.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1950 Sylvania

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

Heater Voltage. . 63 Volts
63 V
Heater Voltage. . 63 Volts
Heater Current (approx.) . 06 Ampere
6 A
Heater Current (approx.) . 06 Ampere
Anode Voltage . 20,000 Volts d¢
20 V
Anode Voltage . 20,000 Volts d¢
Grid No. 4 Voltag;z(Focusmg Electrode) 2500 to +1000 Volts dc¢
1000 V
Grid No. 4 Voltag;z(Focusmg Electrode) 2500 to +1000 Volts dc¢
Anode Voltage? . . . 18,000 Volts dc¢
18 V
Anode Voltage? . . . 18,000 Volts dc¢
Grid No. 4 Voltage . =72 to +396 Volts dc¢
396 V
Grid No. 4 Voltage . =72 to +396 Volts dc¢
Grid No..2 Voltage . . . . . 300 Volts dc¢
300 V
Grid No..2 Voltage . . . . . 300 Volts dc¢
Grid No. 1 Voltage Reqmred for Cutoff* -28 to -72 Volts dc¢
-72 V
Grid No. 1 Voltage Reqmred for Cutoff* -28 to -72 Volts dc¢
Anode Voltage or 16,000 volts, whichever is less.
16 V
Anode Voltage or 16,000 volts, whichever is less.

Data set 02

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Capacitance

Heater Cathode Capacitance
5 pF
Approximate

Other

HighVoltageElectrodeMaximum
20000 V
CRT

Data set 03

1966 Tung Sol Electronic Tubes 4 of 4

Published operating points and test conditions from this source.

SECTION 1

Cathode Ray

Characteristic

Cathode to all other electrodes capacitance
5 pF
WholeTube
Grid 1 to all other electrodes capacitance
6 pF
WholeTube
External conductive coating to anode capacitance maximum
750 pF
WholeTube
External conductive coating to anode capacitance minimum
500 pF
WholeTube
Focusing method
Low-voltage electrostatic
WholeTube
Deflecting method
Magnetic
WholeTube
Horizontal deflection angle
85 degree
WholeTube
Diagonal deflection angle
90 degree
WholeTube
Phosphor color
White
Screen
Persistence
Medium
Screen

Other

Maximum DC anode/accelerator voltage
20000 V
WholeTube
Maximum DC grid 2 voltage
500 V
WholeTube
Maximum negative grid 1 bias magnitude
125 V
WholeTube
Maximum positive peak grid 1 voltage
2 V
WholeTube
Maximum heater-cathode voltage during warm-up
410 V
Warmup15Seconds
DC anode/accelerator voltage
18000 V
TypicalOperation
DC grid 2 voltage
300 V
TypicalOperation